"We have signed a definitive agreement to acquire Aardvark, but we don't have any additional details to share right now," Google spokesman Andrew Pederson said via e-mail, after technology news blog Techcrunch broke the news on Thursday.

Once people sign up for Aardvark, they create a list of contacts, either manually or by importing their contacts from Facebook, Gmail, and other Webmail and IM services, and populate it with those who have already signed up for Aardvark. Users can expand the list to also include friends of friends, as well as members of Facebook groups that they belong to.

Once the list is set up, Aardvark will analyze the contacts' areas of interest and expertise based on information they have provided to Aardvark, preferences stated on their profiles, interactions with their friends and other clues.

Users can send questions to Aardvark through its Web site or through e-mail, Twitter, iPhone devices and IM.

"Aardvark was conceived as the first Social Search engine: a way to find people, not web pages, that have specific information," reads a description of the company on its Web site.

Aardvark was founded in late 2007. Two of its co-founders worked at Google.